Backlight Unit and Display Device Using the Same

ABSTRACT

Provided are a backlight unit and a display device using the same. The backlight unit includes a main support, in which a sheet ear part of an optical sheet is disposed, having a sheet mounting part and an upper hole, a sheet mounting member for mounting the sheet ear part of the optical sheet and formed with a lower hole, and a sheet fixating mechanism coupled to the main support, the optical sheet, and the sheet mounting member to fix the sheet ear part of the optical sheet to the main support. A narrow bezel may be implemented, an optical sheet may be stably secured even in the narrow bezel, and light leakage may be prevented.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(a) to Republic ofKorea Patent Application No. 10-2016-0067564 filed on May 31, 2016,which is incorporated by reference herein in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a backlight unit and a display deviceusing the same.

2. Related Art

In general, liquid crystal displays (LCD), which are light in weight,thin, and driven at low power consumption, have extended applications,and are used in a portable computing devices such as a notebookcomputer, office automation systems, audio/video systems, and interiorand exterior advertisement display devices.

LCDs are mostly transmissive LCDs displaying an image by modulatinglight incident from a backlight unit by controlling a field applied to aliquid crystal layer.

Backlight units may be classified as a direct type backlight unit or anedge type backlight unit. In the direct type backlight unit, a pluralityof light sources are disposed on a lower surface of a diffusion plate toallow light to travel to a rear surface of a liquid crystal panel. Theedge type backlight unit includes a light guide plate and a plurality oflight sources disposed to face a side of the light guide plate.

The edge type backlight unit converts linear light or point lightincident from a light source into planar light on a light guide plateand forces converted light to travel to a rear surface of a liquidcrystal display panel.

The back light unit includes an optical sheet for increasing brightnessby refracting or collecting light, and a main support supporting theoptical sheet.

In particular, in the direct type backlight unit, an optical sheet isdisposed between a diffusion plate and a liquid crystal panel, and inthe edge type backlight unit, the optical sheet is disposed between thelight guide plate and the liquid crystal panel.

Also, the main support supports components included in the backlightunit such as the optical sheet.

SUMMARY

The present disclosure provides a backlight unit capable of implementinga narrow bezel, stably fixating a sheet even in the narrow bezel, andpreventing light leakage, and a display device using the same.

To achieve these and other advantages and in accordance with thedisclosure, as embodied and broadly described herein, a backlight unitincludes: a light source providing light; an optical sheet including asheet ear part extending from one side and formed with an ear part hole;a main support, in which the sheet ear part of the optical sheet isdisposed, formed with a sheet mounting part defined by a carved outbottom portion of the main support between main support fastening partsof the main support, and formed with an upper hole; a sheet mountingmember inserted into the sheet mounting part of the main support toengage the main support fastening parts with the sheet ear part betweenan upper surface of the sheet mounting member and the bottom portion ofthe main support, and formed with a lower hole that aligns with the earpart hole and the upper hole; and a fixating pin inserted through theupper hole of the main support, the ear part hole of the optical sheet,and the lower hole of the sheet mounting member to secure the sheet earpart of the optical sheet between the main support and the sheetmounting member.

The sheet mounting member may include at least one sheet mounting memberfastening part configured to engage with at least one of the mainsupport fastening parts to restrict movement of the sheet mountingmember relative to the main support.

The sheet fixating mechanism may include: a fixating pin maintainingpart disposed an upper surface of the fixating pin and an auxiliary foampad provided on an upper surface of the fixating pin maintaining part.The fixating pin maintaining part may have a greater width than theupper hole, and the auxiliary foam pad may have the same width as thefixating pin maintaining part.

The sheet mounting member may include: sheet mounting member fasteningparts that engage with the main support fastening parts and a sheetguiding part between the sheet mounting member fastening parts having athickness thinner than a thickness of the sheet mounting memberfastening parts, where the sheet guiding part is formed with a lowerhole.

Each of the main support fastening parts of the sheet mounting membermay include a protrusion protruding in a direction parallel to an uppersurface of the sheet guiding part, the protrusion coming into contactwith one of the main support fastening parts.

The sheet mounting member may be pushed in an inward direction towardsthe optical sheet for receiving the fixation pin in the lower hole.

The sheet mounting member may be inserted upwards towards the uppersurface of the sheet mounting member for receiving the fixation pin inthe lower hole.

To achieve these and other advantages and in accordance with the purposeof this specification, as embodied and broadly described herein, adisplay device using a backlight unit includes: the backlight unit; anda display panel displaying an image using light provided from thebacklight unit.

In the backlight unit and the display device using the same according toan embodiment of the present disclosure, since the optical sheet isstably secured using the fixating pin and the sheet mounting member, thebacklight unit and the display device using the same may be applied to amodel of a narrow bezel.

Also, in the backlight unit and the display device using the sameaccording to an embodiment of the present disclosure, since the opticalsheet is secured using the fixating pin and the sheet mounting member,the optical sheet is prevented from being damaged, unlike the relatedart method of coupling the sheet ear part and the protrusion.

Also, in the backlight unit and the display device using the sameaccording to an embodiment of the present disclosure, since the sheet isvertically tightly attached and stably secured by inserting the fixatingpins to the holes provided in the main support, the sheet ear part, andthe sheet mounting member, the sheet may be prevented from beingreleased when a mechanical test and transportation environment, and ahorizontal movement of the sheet may be minimized.

Also, in the backlight unit and the display device using the sameaccording to an embodiment of the present disclosure, the sheet istightly attached and secured to the main support without a gap byinserting the fixating pins to the main support, the sheet ear part, andthe holes provided in the sheet mounting member, and since the upperpart of the fixating pin and the main support are covered using a foampad, light leakage may be effectively prevented.

Also, in the backlight unit and the display device using the sameaccording to an embodiment of the present disclosure, since the sheetmay be secured using the fixating pin mechanism and the auxiliary foampad bonded to each other and the area excluding the sheet fixatingmechanism and the auxiliary foam pad bonded to each other, i.e., theupper part of the main support, is covered using the foam pad, a sheetassembly process and an assembly time required for the process may beshortened.

Further scope of applicability of the present application will becomemore apparent from the detailed description given hereinafter. However,it should be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the scope of the invention will become apparent tothose skilled in the art from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of embodiments of the invention and are incorporated inand constitute a part of this disclosure, illustrate embodiments andtogether with the description serve to explain the principles of theembodiments.

FIG. 1 is a perspective view of a related art display device accordingto an embodiment.

FIG. 2 is a plan view of a display device according to an embodiment.

FIG. 3 is an enlarged perspective view of a part “B” of FIG. 2,illustrating an optical sheet of a display device according to anembodiment.

FIG. 4 is an enlarged exploded perspective view of the part “B” of FIG.2, illustrating that an optical sheet of a display device isdisassembled according to an embodiment.

FIG. 5 is a cross-sectional view of a display device according to anembodiment.

FIG. 6 is a perspective view illustrating an optical sheet of a displaydevice according to an embodiment.

FIG. 7 is a perspective view illustrating an optical sheet of a displaydevice that is disassembled according to an embodiment.

FIG. 8 is a cross-sectional view of a display device according to anembodiment.

FIG. 9 is a view illustrating an example of a sheet mounting member fora backlight unit according to an embodiment.

FIG. 10 is a view illustrating another example of a sheet mountingmember for a backlight unit according to an embodiment.

FIG. 11 is a view illustrating another example of a sheet mountingmember for a backlight unit according to an embodiment.

DETAILED DESCRIPTION

The aforementioned objects, features and advantages of embodiments ofthe present invention will become more apparent through the followingdetailed description with respect to the accompanying drawings. Inadding reference numerals for elements in each figure, it should benoted that like reference numerals already used to denote like elementsin other figures are used for elements wherever possible.

Also, while terms such as “first” and “second,” etc., may be used todescribe various components, such components must not be understood asbeing limited to the above terms. In the description of the presentdisclosure, when it is determined that the detailed description of therelated art would obscure the gist of the present disclosure, thedescription thereof will be omitted.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a related art display device accordingto an embodiment. Referring to FIG. 1, the related art display device 10includes a cover bottom (not shown) having a receiving space, a lightguide plate (not shown) received in the receiving space of the coverbottom, a light source (not shown) received in the receiving space toirradiate light to the light guide plate, a reflective sheet (not shown)disposed below the light guide plate, a main support 13 having a shapeof a rectangular frame, surrounding an outer surface of the coverbottom, and allowing a liquid crystal panel (not shown) to be disposedtherein, and an optical sheet 11 disposed on the light guide plate.

The main support 13 has a rectangular shape to surround the coverbottom, and a sheet mounting part 13 a is provided at an upper surfaceto allow an sheet ear part 11 a of the optical sheet 11 to be disposedtherein, and a protrusion 13 b is formed to protrude from the sheetmounting part 13 b.

Also, the optical sheet 11 includes the sheet ear part 11 a extending inone direction and having a hole 11 h.

As indicated by “A”, the sheet ear part 11 a of the optical sheet 11 iscoupled to the protrusion 13 b protruding in a direction of the mainsupport 13. As the protrusion 13 b is inserted into the hole 11 h formedin the sheet ear part 11 a, the optical sheet 11 is coupled to the mainsupport 13.

In this manner, in the related art display device 10, the protrusion 13b provided in the main support 13 is inserted to the sheet ear part 11 ausing the hole 11 h provided in the sheet ear part 11 a of the opticalsheet 11 to fasten the optical sheet 11.

Also, the optical sheet 11 is secured by bonding a fixating tape 15 tothe sheet ear part 11 a around the protrusion 13 b.

However, the sheet ear part 11 a provided in the optical sheet 11 has awidth W, and thus, a width of an upper surface of the main support 13where the sheet ear part 11 a is disposed and fastened is required to begreater than the width W of the sheet ear part 11 a.

Thus, there is a limitation in reducing a width of the upper surface ofthe main support 13 to reduce a bezel width.

In particular, since a width of the bezel of the display device 10 isincreased due to the width W of the sheet ear part 11 a protruding froma side surface of the optical sheet 11 inserted and fastened to theprotrusion 13 b provided on the upper surface of the main support 13, itis difficult and challenging to implement a narrow bezel.

Also, existing display devices 10 have a large bezel width, and thus,although a width of the sheet ear part 11 a of the sheet is large, thesheet ear part 11 a may be secured to the upper surface of the mainsupport 13.

However, recently, display devices 10 tend to have bezel widths that aredecreased as much as possible, and in order to decrease the bezel width,a width of the main support 13 positioned at an edge of a display device10. However, there are many restrictions in fixating the sheet ear part11 a to the upper surface of the main support 13.

In particular, when the display device 10 is manufactured or used for along period of time, for example, during mechanical testing or in atransportation environment, the sheet ear part 11 a of the optical sheet11 may become released from the protrusion 13 b or damaged due tomovement by the protrusion 13 b.

In addition, in the related art, an escape shape, i.e., a protrusion,may be included in the main support 13 to fixate the optical sheet 11,but a display device 10 having a narrow bezel does not have enough spacefor such an escape shape.

Also, a slight step or gap may be formed between the sheet mounting part13 b on the upper surface of the main support 13 where the sheet earpart 11 a is disposed and the sheet ear part 11 a. A slight step of gapmay also be formed between the protrusion 13 b and the hole 11 h of thesheet ear part 11 a, through which light is leaked.

In particular, as a bezel region is reduced, the optical sheet 11 isinserted and assembled into the protrusion 13 b formed in the mainsupport 13, and an adhesive fixating tape 15 is attached thereto tofixate the optical sheet 11. Here, however, light is leaked through anassembly gap between the fixating tape 15, the optical sheet 11, and theprotrusion 13 b.

Thus, due to the light leakage, the existing structure may not beapplied to a display device without a top case.

FIG. 2 is a plan view of a display device 100 according to anembodiment.

FIG. 3 is an enlarged perspective view of a part “B” of FIG. 2,illustrating the optical sheet 122 of a display device 100 according toan embodiment.

FIG. 4 is an enlarged exploded perspective view of the part “B” of FIG.2, illustrating that an optical sheet 122 of the display device 100 isdisassembled according to an embodiment.

FIG. 5 is a cross-sectional view of a display device 100 according to anembodiment.

Referring to FIGS. 2 to 5, a display device 100 having an optical sheetfixating unit according to an embodiment includes a liquid crystal panel110 and a backlight unit 150 providing light to the liquid crystal panel110.

As shown in FIG. 5, the liquid crystal panel 110 has a color filterarray substrate 112 and a thin film transistor array substrate 114.Liquid crystal cells are arranged in an active matrix form between thecolor filter array substrate 112 and the thin film transistor (TFT)array substrate 114, and each of the liquid crystal cells has a TFT forswitching a video signal.

As a refractive index of each of the liquid crystal cells is changedaccording to a video signal, an image corresponding to the video signalis displayed on the liquid crystal panel 110.

A gate tape carrier package (not shown in FIG. 5) on which a gateintegrated circuit (IC) generating a gate signal is mounted and a datatape carrier package (not shown in FIG. 5) on which a data IC generatinga data signal is mounted are provided on the TFT array substrate 114 ofthe liquid crystal panel 110.

The backlight unit 150 includes a plurality of light sources (not shownin FIG. 5), a light guide plate 120 disposed to face the light sources,an optical sheet 122 disposed above the light guide plate 120, areflective sheet 124 disposed on a rear surface of the light guide plate120, a cover bottom 130 on which the reflective sheet 124 and the lightguide plate 120 are sequentially stacked and received, a main support140 covering an outer side of the cover bottom 130 and allowing theliquid crystal panel 110 to be disposed on an upper portion thereof, anda sheet fixating mechanism 160 fixating the optical sheet 122.

Hereinafter, an edge type backlight unit will be described for thepurposes of description but a technical concept of the presentdisclosure is not limited thereto and may also be applied to a directtype backlight unit.

The light source (not shown) may be implemented as at least any one of alight emitting diode (LED), a hot cathode fluorescent lamp (HCFL), acold cathode fluorescent lamp (CCFL), and an external electrodefluorescent lamp (EEFL). In the present disclosure, a case in which anLED is used as a light source will be described as an example.

The light guide plate 120 is disposed such that at least one sidesurface thereof faces the light source (not shown). The light guideplate 120 converts light incident from the light source into planarlight and allows light to exit to one or more optical sheets 122disposed thereabove. The light guide plate 120 may be formed of amaterial having a high refractive index or transmittance, for example,polymethylenemethacrylate (PMA), polycarbonate (PC), polyethylene (PE),a cyclolefin-based resin (COP), and the like, but the material of thelight guide plate 120 is not limited thereto.

The reflective plate 124 is disposed below the light guide plate 120 andreflects light traveling in a downward direction toward the light guideplate 120 to an upward direction away from the light guide plate 120,i.e., toward the liquid crystal panel 110 to increase light efficiencyof the display device 100.

The optical sheet 122 is disposed between the liquid crystal panel 110and the light guide plate 120, increases uniformity of light incidentthrough the light guide plate 120, and refracts and collects light toincrease brightness. Although not shown in FIG. 5, the optical sheet 122may include a protective sheet, a prism sheet, a diffusion sheet, andthe like. The diffusion sheet diffuses light incident from the lightguide plate 120. The prism sheet includes a microprism having a shape ofa trigonal prism and collects diffused light incident from the diffusionsheet in a direction perpendicular to a rear surface of the liquidcrystal panel 110. The protective sheet protects the prism sheet fromdamage, for example, due to a scratch.

A plurality of sheet ear parts 122 a are formed on one side of theoptical sheet 122. The sheet ear parts 122 a of the optical sheet 122are secured to the main support 140 by the sheet fixating mechanism 160.Also, an ear part hole 122 b, into which a fixating pin 164 is inserted,is formed in each of the sheet ear parts 122 a.

Referring to FIGS. 4 and 5, the main support 140 is a quadrangular moldframe and surrounds and supports other components of the backlight unit150. A sheet mounting part 142 is formed within one side of the mainsupport 140 in which the sheet ear part 122 a of the optical sheet 122is disposed. Main support fastening parts 142 a are provided on bothinner sides of the sheet mounting part 142 such that both sides of asheet mounting member 162 are caught to be secured. The sheet mountingpart 142 is defined by carving out a portion of the main support 140between the main support fastening parts 142 a and underneath an uppersurface of the main support 140.

An upper hole 140 a is formed on the upper surface of the main support140 at the sheet mounting part 142. The upper hole 140 a interfaces withthe sheet mounting part 142 and a fixating pin 164 is inserted into theupper hole 140 a.

Meanwhile, the sheet fixating mechanism 160 includes the sheet mountingmember 162 inserted into the sheet mounting part 142 formed to face thesheet ear part 122 a on one side surface of the main support 140. Thesheet mounting member 162 has a lower hole 162 c into which the fixatingpin 164 is inserted. The fixating pin 164 is inserted through the upperhole 140 a of the main support 140 and inserted into the ear part hole122 b provided in the sheet ear part 122 a of the optical sheet 122 andthe lower hole 162 c provided in the sheet mounting member 162 so as tofixate the optical sheet 122 to the main support 140.

The sheet mounting member 162 has the lower hole 162 c allowing thesheet ear part 122 a to be mounted at a central portion thereof andinterfacing with the ear part hole 122 b of the sheet ear part 122 a,and sheet mounting member fastening parts 162 b fixedly inserted intothe main support fastening part 142 a provided at both inner sides ofthe sheet mounting part 142 of the main support 140.

The sheet mounting member 162 includes a sheet guiding part 162 a towhich the sheet ear part 122 a is guided and mounted, a sheet mountingmember fastening parts 162 b provided on both sides of the sheet guidingpart 162 a and secured to the main support fastening part 142 a providedat both inner sides of the sheet mounting part 142 when the sheetmounting member 162 is inserted to a rear surface of the main support140, and a lower hole 162 c formed in the sheet guiding part 162 a thatinterfaces with the ear part hole 122 b of the sheet ear part 122 a.

The sheet mounting member fastening parts 162 b protrude in a horizontaldirection on both upper sides of the sheet guiding part 162 a, and themain support fastening part 142 a provided in the main support 140 isengaged to be coupled to the sheet mounting member fastening parts 162 bof the sheet mounting member 162.

Also, as shown in FIG. 5, a foam pad 170 covering a portion to which thesheet ear part 122 a is fastened, i.e., an upper part of the fixatingpin 164, is disposed on an upper surface of the main support 140. Thefoam pad 170 may fully block a portion of an upper surface of the mainsupport 140, as well as a portion to which the sheet ear part 122 a ofthe optical sheet 122 is inserted and secured, i.e., a portion to whichthe fixating pin 164 is inserted and fastened.

Thus, in the display device 100 having the optical sheet fixating unit,since the optical sheet 122 is secured by inserting the fixating pin 164to the upper hole 140 a of the main support 140, the ear part hole 122 bof the sheet ear part 122 a, and the lower hole 162 c of the sheetmounting member 162, the optical sheet 122 may be stably secured even ina narrow bezel of the display device 100.

Also, in the display device 100 having the optical sheet fixating unit,since the fixating pin 164 is inserted into the upper hole 140 a of themain support 140, the ear part hole 122 b of the sheet ear part 122 a,and the lower hole 162 c of the sheet mounting member 162, a gap is notformed between the optical sheet 122 and the main support 140, and sincethe foam pad 170 is disposed on an upper surface of the main support 140including the fixating pin 164, light leakage may be effectivelyprevented.

In addition, in the display device 100 having the optical sheet fixatingunit, since the sheet ear part 122 a of the optical sheet 122 isvertically tightly coupled (e.g., attached) and fixed by the fixatingpin 164 between the main support 140 and the sheet mounting member 162,the sheet is prevented from being released in a mechanical testing andtransportation environment of the display device 100, and unwantedhorizontal movement (e.g., due to vibrations during transport or use) ofcomponents of the display device 100 may be effectively reduced orprevented.

FIG. 6 is a perspective view illustrating an optical sheet 222 of adisplay device according to an embodiment.

FIG. 7 is a perspective view illustrating an optical sheet 222 of adisplay device that is disassembled according to an embodiment.

FIG. 8 is a cross-sectional view of a display device 200 according to anembodiment.

Referring to FIGS. 6 to 8, a display device 200 having an optical sheetfixating unit of an embodiment includes a liquid crystal panel 210implementing an image and a backlight unit 250 supplying light to theliquid crystal panel 210.

As shown in FIG. 8, the liquid crystal panel 210 includes a color filterarray substrate 212 and a TFT array substrate 214. Liquid crystal cellsare arranged in an active matrix form between the color filter arraysubstrate 212 and the TFT array substrate 214, and each of the liquidcrystal cells has a TFT for switching a video signal.

As a refractive index of each of the liquid crystal cells is changedaccording to a video signal, an image corresponding to the video signalis displayed on the liquid crystal panel 210.

A gate tape carrier package (not shown in FIG. 8) on which a gateintegrated circuit (IC) generating a gate signal is mounted and a datatape carrier package (not shown in FIG. 8) on which a data IC generatinga data signal is mounted are provided on the TFT array substrate 214 ofthe liquid crystal panel 210.

The backlight unit 250 includes a plurality of light sources (notshown), a light guide plate 220 disposed to face the light sources, anoptical sheet 222 disposed above the light guide plate 220, a reflectivesheet 224 disposed on a rear surface of the light guide plate 220, acover bottom 230 on which the reflective sheet 224, the light guideplate 220, and an optical sheet 222 are sequentially stacked andreceived, a main support 240 covering an outer side of the cover bottom230 and allowing the liquid crystal panel 210 to be disposed on an upperportion thereof, and a sheet fixating mechanism 260 fixating the opticalsheet 222.

Hereinafter, an edge type backlight unit will be described for thepurposes of description but a technical concept of the presentdisclosure is not limited thereto and may also be applied to a directtype backlight unit.

The light source (not shown) may be implemented as at least any one of alight emitting diode (LED), a hot cathode fluorescent lamp (HCFL), acold cathode fluorescent lamp (CCFL), and an external electrodefluorescent lamp (EEFL). In the present disclosure, a case in which anLED is used as a light source will be described as an example.

The light guide plate 220 is disposed such that at least one sidesurface thereof faces the light source (not shown). The light guideplate 220 converts light incident from the light source into planarlight and allows light to exit. to the plurality of optical sheets 222disposed thereabove. The light guide plate 220 The light guide plate 220may be formed of a material having a high refractive index ortransmittance, for example, polymethylenemethacrylate (PMA),polycarbonate (PC), polyethylene (PE), a cyclolefin-based resin (COP),and the like, but the material of the light guide plate 220 is notlimited thereto.

The reflective plate 224 is disposed below the light guide plate 220 andreflects light traveling in a downward direction toward the light guideplate 220 to an upward direction away from the light guide plate 220,i.e., toward the liquid crystal panel 210 to increase light efficiencyof the display device 200.

The optical sheet 222 is disposed between the liquid crystal panel 210and the light guide plate 220, increases uniformity of light incidentthrough the light guide plate 220, and refracts and collects light toincrease brightness. Although not shown in FIG. 8, the optical sheet 222may include a protective sheet, a prism sheet, a diffusion sheet, andthe like. The diffusion sheet diffuses light incident from the lightguide plate 220. The prism sheet includes a microprism having a shape ofa trigonal prism and collects diffused light incident from the diffusionsheet in a direction perpendicular to a rear surface of the liquidcrystal panel 210. The protective sheet protects the prism sheet fromdamage, for example, due to a scratch.

A plurality of sheet ear parts 222 a are formed on one side of theoptical sheet 222. The sheet ear parts 222 a of the optical sheet 222are secured to the main support 240 by the sheet fixating mechanism 260.Also, an ear part hole 222 b, into which a fixating pin 264 is inserted,is formed in each of the sheet ear parts 222 a.

Referring to FIGS. 7 and 8, the main support 240 is a quadrangular moldframe and surrounds and supports other components of the backlight unit250. A sheet mounting part 242 is formed within one side of the mainsupport 240 in which the sheet ear part 222 a of the optical sheet 222is disposed. A main support fastening part 242 a is provided on bothinner sides of the sheet mounting part 242 such that both sides of asheet mounting member 262 are caught to be secured.

An upper hole 240 a is formed on an upper surface of the main support240 at the sheet mounting part 242. The upper hole 240 a interfaces withthe sheet mounting part 242 and a fixating pin 264 is inserted into theupper hole 240 a. A fixating pin mounting part 240 b is provided aroundthe upper hole 240 a present on an upper surface of the main support 240and allows a fixating pin maintaining part 264 a to be mounted thereon.The fixating pin maintaining part 264 a may have a greater width thanthe fixating pin 264.

As illustrated in FIG. 7, the sheet fixating mechanism 260 includes thesheet mounting member 262 inserted into the sheet mounting part 242formed to face the sheet ear part 222 a on one side surface of the mainsupport 240 and having a lower hole 262 c into which the fixating pin264 is inserted, and a fixating pin 264 inserted through the upper hole240 a of the main support 240 and inserted into the ear part hole 222 bprovided in the sheet ear part 222 a of the optical sheet 222 and thelower hole 262 c provided in the sheet mounting member 262 so as tofixate the optical sheet 222. The fixating pin maintaining part 264 a isintegrally formed with the fixating pin 264 on an upper surface of thefixating pin 264, and an auxiliary foam pad 266 is coupled to an upperpart of the fixating pin maintaining part 264 a. The auxiliary foam pad266 may have the same dimensions as the fixating pin maintaining part264 a.

The sheet mounting member 262 includes a sheet guiding part 262 a towhich the sheet ear part 222 a is guided and mounted, a sheet mountingmember fastening parts 262 b provided on both sides of the sheet guidingpart 262 a, inserted into a rear surface of the main support 240 so asto be secured to a main support fastening part 242 a provided at bothinner sides of the sheet mounting part 242, and a lower hole 262 cformed in the sheet guiding part 262 a that interfaces with the ear parthole 222 b of the sheet ear part 222 a.

The sheet mounting member fastening parts 262 b protrudes in ahorizontal direction on both upper sides of the sheet guiding part 262a, and the main support fastening part 242 a provided in the mainsupport 240 is engaged to be coupled to the sheet mounting memberfastening parts 262 b of the sheet mounting member 262.

Also, as shown in FIG. 7, a foam pad 270 covering a portion to which thesheet ear part 122 a is fastened, e.g., a portion excluding an upperpart of the auxiliary foam pad 266 bonded to the fixating pinmaintaining part 264 a of the fixating pin 264, is disposed on an uppersurface of the main support 240. The foam pad 270 may fully shield anupper surface of the main support 240, excluding a portion to which thesheet ear part 222 a of the optical sheet 222 is inserted and fixed,e.g.,, a portion of the auxiliary foam pad 266 as a portion to which thefixating pin 264 is inserted. The auxiliary foam pad 266 may be disposedto be flush with the foam pad 270.

In particular, in a state in which the auxiliary foam pad 266 covers theupper portion of the fixating pin 264, i.e., the upper portion of thefixating pin maintaining part 264, an upper surface of the main support240 excluding the upper part of the fixating pin maintaining part 264 ais covered using the foam pad 270, whereby an assembly process of thedisplay device 200 may be simplified and an assembly time may bereduced. The auxiliary foam pad 266 and the foam pad 270 may beassembled in series or parallel.

Thus, in the display device 200 having an optical sheet fixating unit,since the optical sheet 222 is secured by inserting the fixating pin 264to the upper hole 240 a of the main support 240, the ear part hole 222 bof the sheet ear part 222 a, and the lower hole 262 c of the sheetmounting member 262, the optical sheet 222 may be stably secured even ina narrow bezel of the display device 200.

Also, in the display device 200 having the optical sheet fixating unit,since the fixating pin 264 having the auxiliary foam pad 266 thereon isinserted into the upper hole 240 a of the main support 240, the ear parthole 222 b of the sheet ear part 222 a, and the lower hole 262 c of thesheet mounting member 262, a gap is not formed between the optical sheet222 and the main support 240, and since the foam pad 270 is disposed onan upper surface of the main support 240 excluding the upper part of thefixating pin maintaining part 264 a, light leakage may be effectivelyprevented.

In addition, in the display device 200 having the optical sheet fixatingunit, since the sheet ear part 222 a of the optical sheet 222 isvertically tightly coupled (e.g., attached) and fixed by the fixatingpin 264 between the main support 240 and the sheet mounting member 262,the sheet is prevented from being released in a mechanical testing andtransportation environment of the display device 200, and unwantedhorizontal movement (e.g., due to vibrations during transport or use) ofcomponents of the display device 200 may be effectively reduced orprevented.

Embodiments of the sheet mounting members of the backlight unit will bedescribed with reference to FIGS. 9 to 11.

FIG. 9 is a view illustrating an example of a sheet mounting member 362for a backlight unit according to an embodiment.

Referring to FIG. 9, a sheet mounting member 362 according to anembodiment includes a sheet guiding part 362 a on which the sheet earpart (e.g., 122 a of FIG. 4) of the optical sheet (e.g., 122 of FIG. 5)is mounted, a sheet mounting member fastening parts 362 b provided onboth sides of the sheet guiding part 362 a and having a thicknessgreater than that of the sheet guiding part 362 a, and a lower hole 362c provided in the sheet guiding part 362 a.

The sheet mounting member fastening parts 362 b of the sheet mountingmember 362 have a shape of a protrusion protruding in a horizontaldirection from a lower portion of both side surfaces of the sheetmounting member 362.

The sheet mounting member 362 having the sheet mounting member fasteningparts 362 b as a protrusion protruding in a horizontal direction from alower portion of both side surfaces is inserted into the sheet mountingpart (e.g., 142 of FIG. 4) of the main support (e.g., 140 of FIG. 4) inan inward direction of the main support 140, and the sheet mountingmember fastening parts 362 b as a protrusion is inserted and fastened toa main support fastening part (e.g., 142 a of FIG. 4) provided on bothsides of the main support 140.

Since the sheet mounting member 362 is inserted and assembled to thesheet mounting part 142 of the main support 140 in an inward directionof the main support 140, assembling is facilitated in manufacturing thebacklight unit.

FIG. 10 is a view illustrating another example of a sheet mountingmember 462 for a backlight unit according to an embodiment.

Referring to FIG. 10, a sheet mounting member 462 according to anembodiment includes a sheet guiding part 462 a on which the sheet earpart (e.g., 122 a of FIG. 4) of the optical sheet (e.g., 122 of FIG. 5)is mounted, a sheet mounting member fastening parts 462 b provided onboth sides of the sheet guiding part 462 a and having a thicknessgreater than that of the sheet guiding part 462 a, and a lower hole 462c provided in the sheet guiding part 462 a.

The sheet mounting member fastening parts 462 b of the sheet mountingmember 462 have a shape of a protrusion protruding in a horizontaldirection from upper and lower portion of both side surfaces of thesheet mounting member 462.

The sheet mounting member 462 having the sheet mounting member fasteningparts 462 b as a protrusion protruding in a horizontal direction onupper and lower portions of both side surfaces is inserted into thesheet mounting part (e.g., 142 of FIG. 4) of the main support (e.g., 140of FIG. 4) in an rear surface direction of the main support 140, and thesheet mounting member fastening parts 462 b as a protrusion is insertedand fastened to a main support fastening part (e.g., 142 a of FIG. 4)provided on both sides of the main support 140.

Since the sheet mounting member 462 is inserted and assembled to thesheet mounting part 142 of the main support 140 in the rear surfacedirection of the main support 140, assembling is facilitated inmanufacturing the backlight unit but the sheet mounting member 462 maybe appropriate for vibration impact.

FIG. 11 is a view illustrating another example of a sheet mountingmember 562 for a backlight unit according to an embodiment.

Referring to FIG. 11, a sheet mounting member 562 according to anembodiment includes a sheet guiding part 562 a on which the sheet earpart (e.g., 122 a of FIG. 4) of the optical sheet (e.g., 122 of FIG. 5)is mounted, a sheet mounting member fastening parts 562 b provided onboth sides of the sheet guiding part 562 a and having a thicknessgreater than that of the sheet guiding part 562 a, and a lower hole 562c provided in the sheet guiding part 562 a.

The sheet mounting member fastening parts 562 b of the sheet mountingmember 562 have a shape of a protrusion protruding in a horizontaldirection from a central portion of both side surfaces of the sheetmounting member 562.

The sheet mounting member 562 having the sheet mounting member fasteningparts 562 b as a protrusion protruding in a horizontal direction fromthe central portion of both side surfaces is inserted into the sheetmounting part (e.g., 142 of FIG. 4) of the main support (e.g., 140 ofFIG. 4) in an rear surface direction of the main support 140, and thesheet mounting member fastening parts 562 b as a protrusion is insertedand fastened to a main support fastening part (e.g., 142 a of FIG. 4)provided on both sides of the main support 140.

Since the sheet mounting member 562 is inserted and assembled to thesheet mounting part 142 of the main support 140 in the rear surfacedirection of the main support 140, assembling is facilitated inmanufacturing the backlight unit but the sheet mounting member 562 maybe appropriate for vibration impact.

The foregoing embodiments and advantages are merely exemplary and arenot to be considered as limiting the present disclosure. The presentteachings can be readily applied to other types of apparatuses. Thisdescription is intended to be illustrative, and not to limit the scopeof the claims. Many alternatives, modifications, and variations will beapparent to those skilled in the art. The features, structures, methods,and other characteristics of the embodiments described herein may becombined in various ways to obtain additional and/or alternativeembodiments.

As the present features may be embodied in several forms withoutdeparting from the characteristics thereof, it should also be understoodthat the above-described embodiments are not limited by any of thedetails of the foregoing description, unless otherwise specified, butrather should be considered broadly within its scope as defined in theappended claims, and therefore all changes and modifications that fallwithin the metes and bounds of the claims, or equivalents of such metesand bounds are therefore intended to be embraced by the appended claims.

What is claimed is:
 1. A backlight unit comprising: a light sourceproviding light; an optical sheet including a sheet ear part extendingfrom one side and formed with an ear part hole; a main support, in whichthe sheet ear part of the optical sheet is disposed, the main supportformed with a sheet mounting part, in which the sheet ear part of theoptical sheet is disposed, and an upper hole on an upper surface of themain support; a sheet mounting member inserted into the sheet mountingpart of the main support for mounting the sheet ear part of the opticalsheet and formed with a lower hole; and a fixating pin inserted throughthe upper hole of the main support, the ear part hole of the opticalsheet, and the lower hole of the sheet mounting member to fix the sheetear part of the optical sheet to the main support.
 2. The backlight unitof claim 1, further comprising: a light guide plate disposed to face thelight source; a reflective sheet disposed below the light guide plate; acover bottom in which the reflective sheet, the light source, and thelight guide plate are received; and a foam pad disposed on the uppersurface of the main support to cover the fixation pin.
 3. The backlightunit of claim 1, further comprising: a fixating pin maintaining partdisposed an upper surface of the fixating pin; and an auxiliary foam paddisposed on an upper surface of the fixating pin maintaining part. 4.The backlight unit of claim 3, further comprising: a foam pad disposedon the upper surface of the main support excluding the auxiliary foampad.
 5. The backlight unit of claim 4, wherein the foam pad has a samepattern recess as that of the auxiliary foam pad, the auxiliary foam padbeing positioned within the pattern recess.
 6. The backlight unit ofclaim 1, wherein the sheet mounting member includes: a sheet guidingpart mounted with the sheet ear part of the optical sheet; a sheetmounting member fastening part on a side of the sheet guiding part, andhaving a thickness greater than a thickness of the sheet guiding part.7. The backlight unit of claim 6, wherein the sheet mounting memberfastening part of the sheet mounting member includes a protrusionprotruding in a horizontal direction from a lower portion of the side, aprotrusion protruding in a horizontal direction from each of the lowerportion and an upper portion of the side, or a protrusion protruding ina horizontal direction from a central portion of the side.
 8. Thebacklight unit of claim 7, wherein the sheet mounting member is insertedinto the sheet mounting part of the main support in an inward directionof the main support, the protrusion of the sheet mounting memberfastening part contacting one of the main support fastening parts of themain support.
 9. The backlight unit of claim 7, wherein the sheetmounting member is inserted into the sheet mounting part of the mainsupport in a rear direction of the main support, the protrusion of thesheet mounting member fastening part contacting one of the main supportfastening parts of the main support.
 10. A display device comprising: anoptical sheet including a sheet ear part extending from one side, thesheet ear part formed with an ear part hole; a main support formed witha sheet mounting part, in which the sheet ear part of the optical sheetis disposed, and an upper hole on an upper surface of the main support;a sheet mounting member inserted into the sheet mounting part of themain support to engage the main support fastening parts with the sheetear part between an upper surface of the sheet mounting member and thebottom portion of the main support, the sheet mounting member formedwith a lower hole that aligns with the ear part hole and the upper hole;and a fixating pin inserted through the upper hole, the ear part hole,and the lower hole to secure the sheet ear part of the optical sheetbetween the main support and the sheet mounting member.
 11. The displaydevice of claim 10, further comprising a foam pad on the upper surfaceof the main support to cover the sheet fixating pin.
 12. The displaydevice of claim 10, wherein the sheet mounting member includes at leastone sheet mounting member fastening part configured to engage with atleast one of the main support fastening parts to restrict movement ofthe sheet mounting member relative to the main support.
 13. The displaydevice of claim 10, wherein the fixating pin includes a fixating pinmaintaining part having greater width than the upper hole, and whereinan auxiliary foam pad having a same width as the fixating pinmaintaining part is placed on an upper surface of the fixating pinmaintaining part.
 14. The display device of claim 13, further comprisinga foam pad on the upper surface of the main support, the foam pad havinga carved out portion shaped to correspond to a shape of the auxiliaryfoam pad.
 15. The display device of claim 14, wherein the auxiliary foampad is disposed in the carved out portion of the foam pad and is flushwith the foam pad.
 16. The display device of claim 10, wherein the sheetmounting member comprises sheet mounting member fastening parts thatengage with the main support fastening parts and a sheet guiding partbetween the sheet mounting member fastening parts having a thicknessthinner than a thickness of the sheet mounting member fastening parts,the sheet guiding part formed with a lower hole.
 17. The display deviceof claim 16, wherein each of the sheet mounting member fastening partsof the sheet mounting member includes a protrusion protruding in adirection parallel to an upper surface of the sheet guiding part, theprotrusion coming into contact with one of the main support fasteningparts.
 18. The display device of claim 17, wherein the sheet mountingmember is pushed in an inward direction towards the optical sheet forreceiving the fixating pin in the lower hole.
 19. The display device ofclaim 17, wherein the sheet mounting member is inserted upwards towardsthe upper surface of the sheet mounting member for receiving thefixating pin in the lower hole.